Owen Ryan Ang
Quiz by , created more than 1 year ago

A compilation of objective type questions in Electrical Engineering

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Owen Ryan Ang
Created by Owen Ryan Ang almost 5 years ago
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CURRENT ELECTRICITY

CURRENT ELECTRICITY

Question 1 of 35

1

What are the minimum requirements to cause the flow of current?

Select one of the following:

  • A voltage source, an ammeter, a conductor and an insulator

  • A voltage source, a switch and a resistor

  • A voltage source and a conductor

  • A voltage source, a conductor and an insulator

Explanation

Question 2 of 35

1

Out of the following, select the best conductor of electricity.

Select one of the following:

  • Graphite

  • China Clay

  • Porcelain

  • None of these

Explanation

Question 3 of 35

1

Which of the following statements is correct?

Select one of the following:

  • The resistance does not play an important role in electrical engineering.

  • The resistance of a wire does not depend upon its material.

  • The resistance of most of the materials is independent of the temperature.

  • The resistance of conductor is the hindrance by which the conductor opposes the flow of the current.

Explanation

Question 4 of 35

1

Resistance of a conductor increases when

Select one of the following:

  • its length increases

  • its area increases

  • both length and area increases

  • specific resistance is kept constant

Explanation

Question 5 of 35

1

The specific resistance ρ depends upon

Select one of the following:

  • The area of cross-section and the length of the conductor

  • The material of the conductor, its area of cress-section and length

  • The nature of the material of the conductor only

  • The area of cross-section of the conductor

Explanation

Question 6 of 35

1

The specific resistance ρ is defined as

Select one of the following:

  • resistance of a conductor which has a length of 1 m and cross-section of 1 m2 at 20C

  • resistance of any conductor at 25C

  • resistance of any conductor at 20C

  • resistance of a conductor which has a length of 1 m and cross-section of 1 cm2 at 20C

Explanation

Question 7 of 35

1

The resistance of a conductor, when its temperature is increased

Select one of the following:

  • remains constant

  • increases

  • varies

  • decreases

Explanation

Question 8 of 35

1

It was experimentally found by James Prescott Joule that the heat produced in a current carrying conductor is proportional to

Select one of the following:

  • the square of the current

  • square of resistance

  • the current

  • inversely proportional to time

Explanation

Question 9 of 35

1

The value of Joule's mechanical equivalent of heat, J, is equal to

Select one of the following:

  • 4.2 calories per Joule

  • 2.4 Joules per calorie

  • 4.2 Joules per calorie

  • 4.2 Joules

Explanation

Question 10 of 35

1

Temperature coefficient of a conductor is defined as the

Select one of the following:

  • increase in resistance per ohm per degree centigrade

  • increase in resistance per degree centigrade

  • increase in resistance per degree absolute

  • decrease in resistance per ohm per degree centigrade

Explanation

Question 11 of 35

1

When current flows in a conductor, heat is produced because

Select one of the following:

  • heat α I²

  • of electronic collision

  • of interatomic collision

  • of Joule's law

Explanation

Question 12 of 35

1

Heating effect of current has undesirable side effect in

Select one of the following:

  • electric oven

  • electric iron

  • immersion heater

  • vacuum cleaner

Explanation

Question 13 of 35

1

The resistance of carbon (filament in carbon-filament lamps) when its temperature is decreased

Select one of the following:

  • increases

  • decreases

  • remains the same

  • increases enormously

Explanation

Question 14 of 35

1

The curve representing Ohm's law is

Select one of the following:

  • a parabola

  • linear

  • sine function

  • a hyperbola

Explanation

Question 15 of 35

1

The condition in Ohm's law is that

Select one of the following:

  • ratio V/I should be constant

  • current should be proportional to voltage

  • the temperature should remain constant

  • the temperature should vary

Explanation

Question 16 of 35

1

Ohm's law does not apply to

Select one of the following:

  • conductors

  • conductors when there is change in temperature

  • semiconductor

  • a.c. circuit

Explanation

Question 17 of 35

1

Ohm's law is applicable to

Select one of the following:

  • electric arc

  • rectifying devices

  • gas discharge lamps

  • none of these

Explanation

Question 18 of 35

1

Ohm's law can be applied with certain reservations to

Select one of the following:

  • rectifying devices

  • semiconductors

  • electrolytes

  • thermionic valves

Explanation

Question 19 of 35

1

The presence of an electric current is made known by

Select one of the following:

  • flashing

  • effects produced

  • cracking

  • electric shock

Explanation

Question 20 of 35

1

An electric current can neither be ____ nor ____.

Select one of the following:

  • felt, seen

  • seen, touched

  • seen, produced by any effect

  • produced, felt

Explanation

Question 21 of 35

1

The presence of the current is only made known by the effect it produces. Three important effects are

Select one of the following:

  • heating, electric shock and generation

  • generation, chemical and electric shock

  • heating, magnetic and electric shock

  • heating, magnetic and chemical

Explanation

Question 22 of 35

1

Voltage applied across a circuit, acts as

Select one of the following:

  • mass of electrons

  • negative ions

  • a component of current

  • a force

Explanation

Question 23 of 35

1

In a series circuit the current is

Select one of the following:

  • constant

  • always zero

  • proportional to the resistance

  • different from resistors

Explanation

Question 24 of 35

1

In a parallel circuit the potential difference across the resistance

Select one of the following:

  • varies

  • is different from the applied voltage

  • is sometimes constant

  • is always constant

Explanation

Question 25 of 35

1

The resistance R1 and R2 are connected in parallel. The ratio of values of resistance R1 : R2 is 4 : 1. The currents in R1 : R2 will be equal to

Select one of the following:

  • 1 : 4

  • 1 : 1

  • 4 : 1

  • 4 : 4

Explanation

Question 26 of 35

1

A resistance of 4 ohms is connected across 100 V supply. When another resistor 'R' ohms is connected in parallel with 4 ohms, the total current taken from supply was found to be 50 A. The value of resistance 'R' is

Select one of the following:

  • 2 ohms

  • 3 ohms

  • 5 ohms

  • 4 ohms

Explanation

Question 27 of 35

1

The voltage applied across an electric press was reduced by 50%. The power consumed by the press will be reduced by

Select one of the following:

  • 25%

  • 75%

  • 60%

  • 50%

Explanation

Question 28 of 35

1

Two electric presses are connected in parallel. The resistance of the first press is 100 ohms and that of the second is 300 ohms. The total current taken by both the presses is 4 A. The ratio of current taken by first : second will be equal to

Select one of the following:

  • 2 : 3

  • 1 : 3

  • 3 : 1

  • 1.2 : 3

Explanation

Question 29 of 35

1

Three elements having conductance G1. G2 and G3 are connected in parallel. Their combined conductance will be

Select one of the following:

  • G1 + G2 + G3

  • 1/(G1 + G2 + G3)

  • (G1G2 + G2G3 + G3G1)/(G1 + G2 + G3)

  • 1/(1/G1 + 1/G2 + 1/G3)

Explanation

Question 30 of 35

1

Four resistance R1, R2, R3 and R4 are connected in series against 220 V supply. The resistances are such that R1 > R2 > R3 > R4. The least power consumption will be in

Select one of the following:

  • resistor R1

  • resistor R4

  • resistor R3

  • resistor R2

Explanation

Question 31 of 35

1

When current flows through heater coil it glows but supply wiring does not glow because

Select one of the following:

  • supply wiring is covered with insulation layer

  • current through supply line flows at slower speed

  • supply wires are made of superior material

  • resistance of heater coil is more than that of supply wires

Explanation

Question 32 of 35

1

Resistors commonly used in power circuits are

Select one of the following:

  • carbon resistors

  • etched circuit resistors

  • wire wound resistors

  • deposited metal resistors

Explanation

Question 33 of 35

1

International ohm is defined in terms of resistance of

Select one of the following:

  • a column of mercury

  • a cube of carbon

  • unit length of metal wire

  • a cube of copper

Explanation

Question 34 of 35

1

Which of the following has negative coefficient of resistance?

Select one of the following:

  • wire wound resistor

  • non-metals

  • thermistor

  • metals

Explanation

Question 35 of 35

1

The current carrying capability of the fuse material depends on

Select one of the following:

  • length

  • material

  • cross-sectional area

  • all of these

Explanation

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